Widespread treatment-resistant Trichophyton indotineae infection causing extensive tinea corporis unresponsive to terbinafine has become a major concern in India. This resistance is associated with a mutation in which gene?
- A SQLE gene encoding squalene epoxidase ✓
- B ERG11 (CYP51) gene encoding lanosterol 14-alpha demethylase
- C FKS1 gene encoding glucan synthase
- D ERG3 gene encoding sterol delta-5,6 desaturase
Explanation
Terbinafine resistance in Trichophyton indotineae (the novel species responsible for India's epidemic of recalcitrant tinea) is associated with mutations in the SQLE gene encoding squalene epoxidase — the fungal enzyme that terbinafine inhibits. Point mutations (e.g., F397L, L393S, A448T) in SQLE reduce terbinafine binding, causing high MICs and clinical resistance. T. indotineae infections require itraconazole or voriconazole as alternative treatment. ERG11 (CYP51) mutations cause azole resistance in Candida and Aspergillus. FKS1 mutations cause echinocandin resistance in Candida. ERG3 mutations cause secondary azole resistance in Candida by altering the toxic sterol accumulation.
Reference: Neena Khanna Illustrated Synopsis of Dermatology & STD, 6th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.